When a downlink service of a packet switching (PS, Packet Switching) domain is borne on high speed downlink packet access (high speed downlink packet access, hereinafter referred to as HSDPA), for each HSDPA user, an accompanying dedicated physical channel (Dedicated Physical Channel, hereinafter referred to as DPCH) needs to be allocated, and is used for inner loop power control and a signaling radio bearer (Signal Radio Bearer, hereinafter referred to as SRB).
The DPCH includes a dedicated physical data channel (Dedicated Physical Data Channel, hereinafter referred to as DPDCH) and a dedicated physical control channel (Dedicated Physical Control Channel, hereinafter referred to as DPCCH). The two channels are delivered after being multiplexed together. FIG. 1 shows a frame format of a DPCH (excerpted from the 3GPP 25.211 protocol), where the DPCH further includes other information domains besides a transmit power control (Transmit Power Control, hereinafter referred to as TPC) domain.
When a DPCH is initially established, a base station controller sends establishment signaling to a base station, where the establishment signaling carries initial transmit power, maximum downlink transmit power and minimum downlink transmit power of a DPDCH, and also carries an output power offset value of a DPCCH relative to the DPDCH. The base station adjusts transmit power on the DPDCH by using an inner loop power control algorithm, and limits its final output power to be between the maximum downlink transmit power and the minimum downlink transmit power. Though the power control algorithm can reduce power consumption on the DPCH, the power consumption of the DPCH still takes up a very large part of total downlink power consumption. Through analytic statistics on data of an existing network, it is found that consumed power of each DPCH takes up about 0.7% of total downlink transmit power. In a scenario of an intelligent terminal, the number of online users is very large. Though consumed power of a DPCH of each user is not high, DPCHs of all the users consume a large part of downlink power resources. Assuming that 50 HSDPA users exist, about 35% of downlink power needs to be consumed. A common channel needs to consume about 30% of the downlink power, and adaptive multi-rate coding (Adaptive Multi-Rate and Adaptive Multi-Rate Wideband, hereinafter referred to as AMR) speech further needs to consume about 20% of the downlink power, so a little power, only about 10%, is available to an HSDPA data channel. It can be seen that, the consumed power of the DPCHs of the HSDPA users is far greater than the available power of the HSDPA data channel.
Therefore, how to solve a power consumption problem of the DPCH becomes one of current main research and development directions.